For a wide variety of applications, significant research has been directed to approaches for sensing various forms of pressure. This research has been largely driven by a growing market for pressure-responsive electronic devices including, among others, robotic tactile-sensing implementations such as used in environmental exploration and in industrial robotic manufacturing and touch-responsive display screens such as those having displays, for example, televisions, computer monitors, cell phones, personal digital assistants (PDA's), digital cameras, and music playback devices.
In many of these applications, a tactile-sensing device is used to explore a region of interest by causing engagement between the device and the region of interest. The interaction between the tactile-sensing device and the region of interest produces data that can be used to assess the region of interest. In the context of electronic devices, such as portable communication devices, touch panel/screen displays are designed to interact with a user, an electronic device is used to present or display information to a user for prompting the user to provide input to a touch-responsive aspect of the device, for example, an adjacent touch-responsive surface or the display screen itself. By using the display screen as the touch-responsive surface, the touch screen offers intuitive inputting for a computer or other data processing devices which is especially useful where benefit is realized by eliminating other input devices such as a keyboard and a mouse.
There are many different types of touch-sensing technologies, including capacitive, resistive, infrared, and surface acoustic wave. Each of these technologies sense the position of touches on a surface or screen and each provide certain relative advantages. However, the vast majority of these devices do not respond to the pressure that is applied against the touch screen and for those devices that do respond to applied pressure, they lack sufficient sensitivity for many applications.